The US 3rd Fleet said RIMPAC 2012 involves exercises ranging from disaster relief and maritime security operations to sea control and complex warfighting.

The training missions during the event include amphibious operations; gunnery, missile, anti-submarine and air defense exercises, as well as counter-piracy, mine clearance operations, explosive ordnance disposal and diving and salvage operations.

Global intelligence company Strategic Forecasting, Inc. (Stratfor) believes that People's Liberation Army intelligence analysts are taking a serious look at the Pacific war games.

In a new analysis, "US, China: Exploring the undersea balance," Stratfor said this year’s exercises mark an important step in the projection of power and interoperability between the US and participating nations, as the US military begins its strategic shift toward the Pacific region.

Stratfor believes Beijing will be particularly interested in US nuclear-powered submarines that are on display during the exercises.

In 1998, the US Navy allowed a small Chinese military team to observe RIMPAC. Another contingent was also allowed to observe the Valiant Shield exercises off Guam in 2006.

The invitations, however, are the exceptions to the rule that is the National Defense Authorization Act of 2000 that prevents the US armed forces with having certain direct military-to-military contact with China.

Being left out in this year's RIMPAC exercises has left China brooding.

"These military exercises have highlighted US deployed intention to realize the 'stability under the US rule,' and transform the 21st century into a 'Pacific Century of the US," the Chinese military newspaper said.

"The US uses military exercise diplomacy to accelerate its eastward shift of strategic focus, and enhance its influence in the Asia-Pacific region," it added. "Since Obama took office, the US has proposed a new approach to shift its strategic focus eastward, attempting to consolidate its dominance in the Asia-Pacific region and maintain its global dominance."

"In terms of military affairs, the U.S. has not only tried to increase its military presence in the Asia-Pacific region and prepared to shift 60% of its naval troops to the Asia-Pacific region, but also vigorously promoted its military exercise diplomacy," the People's Liberation Army Daily said.

A Communist Party-controlled tabloid, the Global Times, has a sarcastic, sourgrape view of the 2012 RIMPAC exercises and China's non-invite.

"Those who have some knowledge of the military know that the more countries join such an exercise, the less military significance it has," the publication said in a non-bylined opinion piece. "It is more like a diplomatic and political show put on by the US."

"The US uses its military as a diplomatic resource," it added. "The exercise is obviously aimed at expanding the US' influence. The move comes as Russia and India announce their presence in the Asia-Pacific. If China joins the exercise, it would be no different to an international conference."

The publication, which has been the subject of a confidential US embassy memo for its hardline, ultranationalist views, also descibed the RIMPAC war games are "nothing but a big party held by the US."

"Watching from afar, China is feeling uncomfortable. But it should be forgotten soon," it said. "China should get used to being left out in the cold by the US. This is normal, as China is becoming the world's No.2."

"China should take it easy. If we become entangled in the US' moves, we will believe that the US is shaping a geopolitical pressure against China. This not only puts stress on China, but also encourages the US' allies and those that have frictions with China. We will think that the exercise enhances the US' central position and isolates China," the Global Times opinion piece said.

It believes that the war games will not isolate China.

"China's influence on international relations means more than the RIMPAC," it said. "China has no intention of confronting the US' power. None of the 21 nations participating in the exercise would like to see a confrontation between the two in the Pacific, and neither does the US."